Undervolting problem - Disappearance of Graphic card

I've post that in the main tread for undervolting but as it hasn't been bumped for some time, I'm thinking I could have more attention here. I hope it's not too incorrect.

I've tried to undervolt my netbook, which is an Asus K42JV and I have encountered some problem; well I've encountered one big problem: my graphic card has disapeared.
The computer works on optimus technology, switching between an intel card and an Nvidia Geforce 335MX.

I was following the procedure, using different sofwares because the ones proposed here don't work with my config and I was lowering the thing and gaining significantly in temperature until I dropped 8 degrees and lost my Nvidia Graphic card to have only my Intel recognized.

The softwares were : Cpuz CPUID, Crystal CPUID, OCCT Perestroïka; I had found them here: Mon portable chauffe ? Quelles solutions y a t-il ? | CommentCaMarche for those who read french.
The instructions where noticeably the same as those given here exept with different sofwares.

I had problems before with the recognization of my GC but after trying to reinstall all drivers, and not being able to because it doesn't find any card, I don't know what to do. Well I will probably try to make a system recovery but I wanted to know if anybody has any idea of what happened.

Particularly, could it be material ?